Thu, 05 Jul 2012

What about potassium additives?

Last month, I blogged about the growing body of evidence that has nephrology healthcare professionals worried about the potential public health impact of phosphate additives. I talked about the risks to kidney patients and the potential for risk to all Canadians.

But what about potassium additives?

These are a concern for people who can’t eliminate potassium from the body and this includes some, but not all, kidney patients. Potassium is usually very tightly regulated in the body and levels that are too high or too low can be life threatening. Many medications (such as certain blood pressure meds or diuretics) can affect potassium levels. Most people on conventional (3 times a week) hemodialysis need to limit their potassium but some kidney patients may need to increase their dietary potassium, or even take a supplement.

For those who need to limit potassium, additives are a major concern – especially potassium chloride. Many companies use potassium chloride in place of sodium chloride when making sodium reduced products. These can provide a huge amount of potassium. The food laws in Canada do require that if a company uses potassium chloride or KCl in place of sodium then the Nutrition Facts Table must include the total potassium content. This can be an important clue to lead you to check the ingredients list.

For example, a low sodium vegetable cocktail that has potassium chloride in place of sodium chloride provides a whopping 700mg of potassium in only 163mL of juice. That’s like eating two small bananas! Indeed, regular vegetable cocktail provides less than half this amount and is still considered a high potassium food.

Another place we see a lot of potassium chloride is in salt substitutes that are a white powder. Generally these products come with a warning that some kidney and heart patients should avoid them but the words are tiny and many people miss the warning. I recall several years ago going out to a retirement home where two of my patients had high potassium levels we just couldn’t figure out. When I arrived I noticed every table in the dining room had a bottle of salt substitutes containing potassium right in the centre!

Bottom line: If you need to follow a low potassium diet read your labels, be suspicious if something has a low sodium claim and don’t use white powder salt substitutes.